Figure 5

Images and intensity maps from analysis of a thin section of granule Fresh-1. a) reflected light image of granule Fresh-1 collected within 1 day of secretion, scale bar is 200 μm; μ-FTIR intensity maps for (b) ν₂ (855–890 cm⁻¹), (c) ν₄ (695–716 cm⁻¹) and (d) ν₂/ν₄ ratio map with high intensity areas indicative of ACC rich regions; (e) cluster analysis map showing 6 clusters, f) component regression intensity map for ACC, g) component regression intensity map for calcite, h) electron microprobe Mg distribution map showing the concentric growth features in the granule. For the μ-FTIR intensity maps, red indicates high intensity, blue indicates low intensity, while for the elemental maps bright indicates higher concentrations.